use this type of filter when resizing an image.
Use this option to affect the resizing operation of an image (see
-geometry). Choose from these filters:
Point
Box
Triangle
Hermite
Hanning
Hamming
Blackman
Gaussian
Quadratic
Cubic
Catrom
Mitchell
Lanczos
Bessel
Sinc
The default filter is Mitchell.
-flip
create a "mirror image" by reflecting the scanlines in the vertical
direction.
-flop
create a "mirror image" by reflecting the image
scanlines in the horizontal direction.
-font name
use this font when annotating the image with text.
If the font is a fully qualified X server font name, the font is obtained
from an X server (e.g.
-*-helvetica-medium-r-*-*-12-*-*-*-*-*-iso8859-*). To
use a TrueType font, precede the TrueType filename with a @ (e.g.
@times.ttf). Otherwise, specify a Postscript font (e.g.
helvetica).
-frame <width>x<height+<outer bevel width>+<inne
r bevel width>
surround the image with an ornamental border. See
X(1) for details about the geometry specification.
The color of the border is specified with the
-mattecolor command line option.
-gamma value
level of gamma correction.
The same color image displayed on two different
workstations may look different due to differences in
the display monitor. Use gamma correction to adjust
for this color difference. Reasonable values extend
from 0.8 to 2.3.
You can apply separate gamma values to the red,
green, and blue channels of the image with a gamma
value list delineated with slashes (i.e. 1.7,2.3,1.2).
Use +gamma to set the image gamma level without actually adjusting
the image pixels. This option is useful if the image is of a known
gamma but not set as an image attribute (e.g. PNG images).
-geometry <width>{%}x<height>{%}{!}{<}{>}
preferred size and location of the Image window. See
X(1) for details about the geometry specification.
By default, the window size is the image size and the
location is chosen by you when it is mapped.
By default, the width and height are maximum values.
That is, the image is expanded or contracted to fit
the width and height value while maintaining the
aspect ratio of the image. Append an exclamation
point to the geometry to force the image size to
exactly the size you specify. For example, if you
specify 640x480! the image width is set to 640 pixels
and height to 480. If only one factor is specified,
both the width and height assume the value.
To specify a percentage width or height instead,
append %. The image size is multiplied by the width
and height percentages to obtain the final image
dimensions. To increase the size of an image, use a
value greater than 100 (e.g. 125%). To decrease an
image's size, use a percentage less than 100.
Use > to change the dimensions of the image only
if its size exceeds the geometry specification. < resizes
the image only if its dimensions is less than the geometry
specification. For example, if you specify 640x480> and the
image size is 512x512, the image size does not change. However, if
the image is 1024x1024, it is resized to 640x480.
Use < to change the dimensions of the image only
if its size exceeds the geometry specification. > resizes
the image only if its dimensions is less than the geometry
specification. For example, if you specify 640x480> and the
image size is 512x512, the image size does not change. However, if
the image is 1024x1024, it is resized to 640x480.
There are 72 pixels per inch in PostScript coordinates.
-gravity type
direction text gravitates to when annotating the image: NorthWest, North,
NorthEast, West, Center, East, SouthWest, South, SouthEast.
See X(1) for details about the gravity specification.
The direction you choose specifies where to
position the text when annotating the image. For example Center
gravity forces the text to be centered within the image.
By default, the image gravity is NorthWest.
-implode factor
implode image pixels about the center. Specify factor as the
percent implosion (0 - 99.9%) or explosion (-99.9 - 0%).
-interlace type
the type of interlacing scheme: None, Line, Plane,
or Partition. The default is None.
This option is used to specify the type of interlacing scheme for raw
image formats such as RGB or YUV. None means do not
interlace (RGBRGBRGBRGBRGBRGB...), Line uses scanline interlacing
(RRR...GGG...BBB...RRR...GGG...BBB...), and Plane uses plane
interlacing (RRRRRR...GGGGGG...BBBBBB...). Partition is like plane
except the different planes are saved to individual files (e.g. image.R,
image.G, and image.B).
Use Line, or Plane to create an interlaced GIF
or progressive JPEG image.
-label name
assign a label to an image.
Use this option to assign a specific label to the
image. Optionally you can include the image
filename, type, width, height, or other image attribute by
embedding special format character. See -comment for details.
For example,
-label "%m:%f %wx%h"
produces an image label of MIFF:bird.miff 512x480 for an
image titled bird.miff and whose width is 512 and height
is 480.
If the first character of string is @, the image label is
read from a file titled by the remaining characters in the
string.
When converting to PostScript, use this option to specify
a header string to print above the image. Specify the label font with
-font.
-layer type
the type of layer: Red, Green, Blue,
or Matte.
Use this option to extract a particular layer from the image.
Matte, for example, is useful for extracting the opacity values
from an image.
-linewidth value
set the width of a line. See -draw for further
details.
-loop iterations
add Netscape loop extension to your GIF animation.
A value other than zero forces the animation to repeat itself up to
iterations times.
-map filename
choose a particular set of colors from this image.
By default, color reduction chooses an optimal set of colors that
best represent the original image. Alternatively, you can choose a
particular set of colors from an image file with this option. Use
+map to reduce all images provided on the command line to a single
optimal set of colors that best represent all the images.
-matte
store matte channel if the image has one otherwise create an opaque one.
-modulate value
vary the brightness, saturation, and hue of an image.
Specify the percent change in brightness, the color
saturation, and the hue separated by commas.
For example, to increase the color brightness by 20% and
decrease the color saturation by 10% and leave the
hue unchanged, use: -modulate 20/-10.
-monochrome
transform the image to black and white.
-morph
morphs an image sequence.
Both the image pixels and size are linearly interpolated to give the
appearance of a meta-morphosis from one image to the next.
-negate
apply color inversion to image.
The red, green, and blue intensities of an image are
negated. Use +negate to only negate the grayscale pixels of the
image.
-noise
add or reduce noise in an image.
The principal function of noise peak elimination
filter is to smooth the objects within an image
without losing edge information and without creating
undesired structures. The central idea of the
algorithm is to replace a pixel with its next
neighbor in value within a 3 x 3 window, if this
pixel has been found to be noise. A pixel is defined
as noise if and only if this pixel is a maximum or
minimum within the 3 x 3 window.
Use +noise followed by a noise type to add noise to an image.
Choose from these noise types:
Uniform
Gaussian
Multiplicative
Impulse
Laplacian
Poisson
-normalize
transform image to span the full range of color
values.
This is a contrast enhancement technique.
-opaque color
change this color to the pen color within the image.
See -pen for more details.
-page <width>{%}x<height>{%}{+-}<x
offset>{+-}<y offset>{!}{<}{>}
size and location of an image canvas.
Use this option to specify the dimensions of the
PostScript page in dots per inch or a TEXT page in
pixels. The choices for a Postscript page are:
11x17 792 1224
Ledger 1224 792
Legal 612 1008
Letter 612 792
LetterSmall 612 792
ArchE 2592 3456
ArchD 1728 2592
ArchC 1296 1728
ArchB 864 1296
ArchA 648 864
A0 2380 3368
A1 1684 2380
A2 1190 1684
A3 842 1190
A4 595 842
A4Small 595 842
A5 421 595
A6 297 421
A7 210 297
A8 148 210
A9 105 148
A10 74 105
B0 2836 4008
B1 2004 2836
B2 1418 2004
B3 1002 1418
B4 709 1002
B5 501 709
C0 2600 3677
C1 1837 2600
C2 1298 1837
C3 918 1298
C4 649 918
C5 459 649
C6 323 459
Flsa 612 936
Flse 612 936
HalfLetter 396 612
For convenience you can specify the page size by media
(e.g. A4, Ledger, etc.). Otherwise, -page behaves much like
-geometry (e.g. -page letter+43+43>).
To position a GIF image, use -page
{+-}<x offset>{+-}<y offset>
(e.g. -page +100+200).
For a Postscript page, the image is sized as in -geometry and
positioned relative to the lower left hand corner of the page by
{+-}<x offset>{+-}<y offset>.
Use -page 612x792>, for example, to center the image within the
page. If the image size exceeds the Postscript page, it is reduced to fit the
page.
The default page dimensions for a TEXT image is 612x792.
This option is used in concert with -density.
-paint radius
simulate an oil painting.
Each pixel is replaced by the most frequent color in a circular
neighborhood whose width is specified with radius.
-pen color
set the color of the font or opaque color. See -draw for further
details.
See X(1) for details about the color specification.
-pointsize value
pointsize of the Postscript font.
-preview type
image preview type.
Use this option to affect the preview operation of an image
(e.g. convert -preview Gamma Preview:gamma.gif).
Choose from these previews:
Rotate
Shear
Roll
Hue
Saturation
Brightness
Gamma
Spiff
Dull
Grayscale
Quantize
Despeckle
ReduceNoise
Add Noise
Sharpen
Blur
Threshold
EdgeDetect
Spread
Shade
Raise
Segment
Solarize
Swirl
Implode
Wave
OilPaint
CharcoalDrawing
JPEG
The default preview is JPEG.
-flip
create a "mirror image" by reflecting the scanlines in the vertical
direction.
-quality value
JPEG/MIFF/PNG compression level.
For the JPEG image format, quality is 0 (worst) to 100 (best).
The default quality is 75.
Quality for the MIFF and PNG image format sets the amount of image
compression (quality / 10) and filter-type (quality % 10). Compression quality
values range from 0 (worst) to 100 (best). If filter-type is 4
or less, the specified filter-type is used for all scanlines:
0: none
1: sub
2: up
3: average
4: Paeth
If filter-type is 5, adaptive filtering is used when quality
is greater than 50 and the image does not have a color map,
otherwise no filtering is used.
If filter-type is 6 or more, adaptive filtering with
minimum-sum-of-absolute-values is used.
The default is quality is 75. Which means nearly the best compression
with adaptive filtering.
For further information, see the PNG specification
(RFC 2083).
-raise <width>x<height>
lighten or darken image edges to create a 3-D effect. See X(1)
for details about the geometry specification.
Use -raise to create a raised effect, otherwise use +raise.
-region <width>x<height>{+-}<x
offset>{+-}<y offset>
apply options to a portion of the image.
By default, any command line options are applied to the entire image. Use
-region to restrict operations to a particular area of the image.
-roll {+-}<x offset>{+-}<y offset>
roll an image vertically or horizontally. See X(1)
for details about the geometry specification.
A negative x offset rolls the image left-to-right. A
negative y offset rolls the image top-to-bottom.
-rotate degrees{<}{>}
apply Paeth image rotation to the image.
Use > to rotate the image only if its width exceeds the
height. < rotates the image only if its width is less than
the height. For example, if you specify -90> and the image size
is 480x640, the image is not rotated by the specified angle. However,
if the image is 640x480, it is rotated by -90 degrees.
Empty triangles left over from rotating the image are
filled with the color defined as bordercolor (class
borderColor). See X(1) for details.
-sample geometry
scale image with pixel sampling. See -geometry for
details about the geometry specification.
-scene value
image scene number.
-seed value
pseudo-random number generator seed value.
-segment <cluster threshold>x<smoothing threshold>
segment an image by analyzing the histograms of the color components and
identifying units that are homogeneous with the fuzzy c-means technique.
Specify cluster threshold as the number of pixels in each cluster
must exceed the the cluster threshold to be considered valid. Smoothing
threshold eliminates noise in the second derivative of the
histogram. As the value is increased, you can expect a smoother second
derivative. The default is 1.5. See Image Segmentation
for details.
-shade <azimuth>x<elevation>
shade the image using a distant light source.
Specify azimuth and elevation as the position of the light
source. Use +shade to return the shading results as a grayscale image.
image.
-sharpen factor
sharpen an image. Specify factor as the percent
enhancement (0.0 - 99.9%).
-shear <x degrees>x<y degrees>
shear the image along the X or Y axis by a positive
or negative shear angle.
Shearing slides one edge of an image along the X or Y
axis, creating a parallelogram. An X direction shear
slides an edge along the X axis, while a Y direction
shear slides an edge along the Y axis. The amount of
the shear is controlled by a shear angle. For X
direction shears, x degrees is measured relative to
the Y axis, and similarly, for Y direction shears y
degrees is measured relative to the X axis.
Empty triangles left over from shearing the image are
filled with the color defined as bordercolor (class
borderColor). See X(1) for details.
-size <width>{%}x<height>{%}{+offset}{!}
width and height of the image.
Use this option to specify the width and height of
raw images whose dimensions are unknown such as GRAY,
RGB, or CMYK. In addition to width and height, use
-size to skip any header information in the image or tell
the number of colors in a MAP image file, (e.g. -size 640x512+256).
For Photo CD images, choose from these sizes:
192x128
384x256
768x512
1536x1024
3072x2048
Finally, use this option to choose a particular resolution layer of a JBIG
or JPEG image (e.g. -size 1024x768).
-solarize factor
negate all pixels above the threshold level. Specify factor
as the percent threshold of the intensity (0 - 99.9%).
This option produces a solarization effect seen when exposing
a photographic film to light during the development process.
-spread amount
displace image pixels by a random amount.
Amount defines the size of the neighborhood around each pixel to
choose a candidate pixel to swap.
-swirl degrees
swirl image pixels about the center.
Degrees defines the tightness of the swirl.
-transparency color
make this color transparent within the image.
-texture filename
name of texture to tile onto the image background.
-threshold value
threshold the image.
Create a bi-level image such that any pixel intensity that
is equal or exceeds the threshold is reassigned the maximum intensity otherwise
the minimum intensity.
-treedepth value
Normally, this integer value is zero or one. A zero
or one tells display to choose a optimal tree depth
for the color reduction algorithm.
An optimal depth generally allows the best
representation of the source image with the fastest
computational speed and the least amount of memory.
However, the default depth is inappropriate for some
images. To assure the best representation, try
values between 2 and 8 for this parameter. Refer to
quantize for more details.
The -colors or -monochrome option is required for
this option to take effect.
-undercolor <undercolor
factor>x<black-generation
factor>
control undercolor removal and black generation on CMYK
images.
This option enables you to perform undercolor removal
and black generation on CMYK images-- images to be
printed on a four-color printing system. You can con-
trol how much cyan, magenta, and yellow to remove from
your image and how much black to add to it. The stan-
dard undercolor removal is 1.0x1.0. You'll frequently
get better results, though, if the percentage of black
you add to your image is slightly higher than the per-
centage of C, M, and Y you remove from it. For example
you might try 0.5x0.7.
-verbose
print detailed information about the image.
This information is printed: image scene number;
image name; image size; the image class (DirectClass
or PseudoClass); the total number of unique colors;
and the number of seconds to read and transform the
image. Refer to miff for a description
of the image class.
If -colors is also specified, the total unique colors
in the image and color reduction error values are
printed. Refer to quantize for a
description of these values.
-view string
FlashPix viewing paramters.
-wave <amplitude>x<wavelength>
alter an image along a sine wave.
Specify amplitude and wavelength to effect the
characteristics of the wave.
Options are processed in command line order. Any option you
specify on the command line remains in effect until it is
explicitly changed by specifying the option again with a
different effect.
By default, the image format is determined by its magic
number. To specify a particular image format, precede the
filename with an image format name and a colon (i.e.
ps:image) or specify the image type as the filename suffix
When you specify X as your image type, the filename has
special meaning. It specifies an X window by id, name, or
root. If no filename is specified, the window is selected
by clicking the mouse in the desired window.
Specify input_file as - for standard input,
output_file as -
for standard output. If input_file has the extension .Z or
.gz, the file is uncompressed with uncompress or
gunzip
respectively. If output_file has the extension .Z or
.gz,
the file size is compressed using with compress or gzip
respectively. Finally, precede the image file name with |
to pipe to or from a system command.
Use an optional index enclosed in brackets after a file name to specify
a desired subimage of a multi-resolution image format like Photo CD
(e.g. img0001.pcd[4]) or a range for MPEG images (e.g. video.mpg[50-75]).
A subimage specification can be disjoint (e.g. image.tiff[2,7,4]).
For raw images, specify a subimage with a geometry (e.g. -size 640x512
image.rgb[320x256+50+50]).
Single images are written with the filename you specify.
However, multi-part images (i.e. a multi-page PostScript
document with +adjoin specified) are written with the filename followed
by a period (.) and the scene number. You can change this behavior by
embedding a printf format specification in the file name.
For example,
- image%02d.miff
converts files image00.miff, image01.miff, etc.